The present invention relates to an arrangement for optimizing the running speed of a track-bound vehicle whose movement is determined by an automatic control system preassigning speeds and braking curves, and which is accelerated up to the permissible speed at a predetermined rate or with maximum propulsion power.
In continuous automatic train control it is common practice to preassign to the vehicles maximum permissible speeds and braking curves which a fixed computer system determines from the train-specific and line data. If the speed of the train is lower than the maximum permissible speed, the train is accelerated automatically -- first at a predetermined rate and later, when this is no longer possible for power reasons -- with maximum power until the maximum permissible speed has been reached. The predetermined acceleration rate is as high as possible to achieve a short running time.
This control method is based on the assumption that predominantly long track sections are travelled at the maximum permissible speed. This is not always the case, however. On the contrary, it frequently happens that only a short portion of the line ahead is free, e.g. when a train with a high preassigned acceleration rate and a high maximum speed must follow a slower train. The resulting unnecessary acceleration and braking processes of the faster train lead to a high energy consumption and rapid wear of brakes and switch gear.
These disadvantages could be largely overcome by introducing a coasting phase as a third possible running condition besides the acceleration phase and the braking phase. In an article by J. Glimm, AET (30)-1975, a vehicle control system is discussed which uses a coasting phase to achieve oscillation-free control. With the "near-optimum control of train separation" described there, the nominal speed is reduced in a coasting phase and a subsequent braking phase with fixed retardation. However, since the system determines the nominal speeds from the distance to a phantom vehicle ahead which is simulated on a computer, it cannot be used in continuous automatic train control. Moreover, the article deals exclusively with automatic control theory and makes no proposals for the realization of a near-optimum control of train separation.